Question: Factor the following expression: $72x^2 - 50$
We can start by factoring a ${2}$ out of each term: $ {2}({36x^2} - {25})$ The second term is of the form ${a^2} - {b^2}$ , which is a difference of two squares so we can factor it as ${2}({a} + {b}) ({a} - {b})$ What are the values of $a$ and $b$ $ a = \sqrt{36x^2} = 6x$ $ b = \sqrt{25} = 5$ Use the values we found for $a$ and $b$ to complete the factored expression, ${2}({a} + {b}) ({a} - {b})$ So we can factor the expression as: ${2}({6x} + {5}) ({6x} - {5})$